Fault-tolerant gamma interconnection networks

Modifications to the gamma interconnection network (GIN), which is composed of 3*3 basic building blocks, with interconnecting patterns between stages following the plus-minus-2/sup i/ functions, are discussed. The gamma network is modified by altering the interconnecting patterns between stages so as to create totally disjoint paths from any source (S) to any destination (D), ensuring high terminal reliability between every (S, D) pair. The network is called fault-tolerant GIN (FTGIN) since it can tolerate an arbitrary single fault. If several building blocks (i.e. 3*3 switches) are fabricated in one VLSI chip, the layout area and pin count are smaller for the FTGIN than for its GIN counterpart as a result of the change in the interconnection patterns, offering potential cost reduction. A lower bound on the terminal reliability of the FTGIN is derived, showing significant terminal reliability improvement over the conventional gamma network.<>